VERTICAL ADDITION OF AN EXISTING MASONRY BUILDING BY A COLD-FORMED STEEL STRUCTURE

In the last years, the concept of sustainable development has emerged due to the apparent inadequacy of energy production to meet consumer demands without causing impact on the life quality. The construction field plays a major role in the environmental issue, since it represents the greatest impact source. In this policy framework based on the reduction of energy consumption, the redevelopment of existing buildings has an important role, since it aims to improve their energetic behaviour. Within such a scenario addressed to the energy saving, the difficulty to find living volumes in cities is recently appearing. This is relevant especially for Italian historic city centres, where the exponential growth of population is remarkable. Therefore, economic and environmental structural solutions able to mediate the features of existing built heritage with the above new requirements are needed. Among these, the vertical addition is an alternative to the traditional solutions of growth of cities. In this context, Italian legislation has drawn up new regulations, which are able to meet the new requirements. The study presented in this paper is related to this aspect. It deals with the structural behaviour assessment of an existing public masonry building, which is the most common structural type in the South Italy constructive tradition, subjected to a vertical addition through the cold-formed steel technology. First, the design idea has been presented, it dealing with the use of a steel stick-built construction, and, subsequently, its effectiveness in improving the number of storey of the existing building by limiting strengthening interventions has been proved by static non-linear analyses. Finally, on the basis of the achieved numerical results, the vertical addition steel structure has been erected and applied to the masonry building, so to represent the first novel application of a light and sustainable steel system for increasing the number of living units within Italian historical centres.